Is it possible to hide particle emitters in the viewport without hiding particles?
Another way (similar to Michal's answer) is to use a Mask modifier:

Add an empty vertex group to the particle emitter by pressing the + button in Object Data &gt; Vertex Groups:



Add a mask modifier after the particle system with the empty vertex group:



There was a bug in 2.69; in order for the mask modifier to work you had to assign and remove some geometry to the vertex group. It has since been fixed.